Transmission fluid pressure switches C and D report whether a clutch circuit is pressurised. They are more widespread than A and B: GM's 6L80/6L90 and 6T40/6T70 six-speeds put switch C on the 2-6 brake and D on the 1-2-3-4 clutch, Allison uses them for its third shift valve and its reverse switch, Ram's RFE gearboxes for the clutch pressure switches in the solenoid block. Ford reports pressure faults under its solenoid codes. P0872 means switch C reports pressure while its clutch is exhausted. GM checks it only when the 2-6 brake is commanded below 50 kPa, after a temperature-dependent delay, and counts one fault per clutch change: 10 on the 6L80, 18 on the 2010 6T70; listed as 'special no trip', without MIL. Allison 2007 sets it when switch 3 reports pressure for over 20 ms with the valve at rest, type A.
Medium severity. Can I keep driving?Drive gently to a repair shop. If it slips, you hear clunks, or it loses its gears, do not keep driving.
Symptoms
- Code stored in the gearbox module; on GM without MIL, on Allison with MIL
- Harsh shifts, possibly substitute gear
Most likely causes
- Pressure switch stuck closed or shorted internally
- Signal wire shorted to ground inside the gearbox
- Clutch circuit does not exhaust: dirt, sticking valve
- Gearbox module
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: hard
- It can trigger limp mode.
What each character of P0872 means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- 8: Transmission
- 72: Specific fault in that system
Frequently asked questions
Can I keep driving with code P0872?
Drive gently to a repair shop. If it slips, you hear clunks, or it loses its gears, do not keep driving.
What causes code P0872?
The most common causes are: pressure switch stuck closed or shorted internally; signal wire shorted to ground inside the gearbox; clutch circuit does not exhaust: dirt, sticking valve.
Related codes
- P0870Transmission Fluid Pressure Sensor/Switch C Circuit
- P0871Transmission Fluid Pressure Sensor/Switch C Circuit Range/Performance
- P0873Transmission Fluid Pressure Sensor/Switch C Circuit High
- P0877Transmission Fluid Pressure Sensor/Switch D Circuit Low
- P0989Transmission Fluid Pressure Sensor/Switch E Circuit Low
- P0762Shift Solenoid C Stuck On
Sources
- gsi.ext.gm.com: 11OBDG07 TRANS Diagnostics
- gsi.ext.gm.com: 10OBDG08 TRANS Diagnostics
- gsi.ext.gm.com: 07 GRP15 Allison 1000
- gsi.ext.gm.com: 2006trans9
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.